Technical Abstract:
DNA sequence analysis and other DNA-based methodologies have transformed the way in which yeasts are identified and classified. Development of species-specific gene sequence databases has provided a barcode system for rapid identification of known species and the recognition of undescribed species. The barcode databases are widely used in clinical laboratories, quality control laboratories for the food industry and for numerous other needs including studies in ecology and biodiversity. The availability of gene sequence databases has resulted in the doubling of known yeasts in the past 10 years. Multigene sequence analyses have resolved phylogenetic relationships among both ascomycetes and basidiomycetes. Members of the Ascomycota are found in three lineages with typical budding yeasts in a single lineage, the Saccharomycotina. The Basidiomycota also was resolved into three major lineages, but for this phylum, yeasts are present in all three lineages. Multigene analyses have resulted in reclassification of the yeasts into phylogenetically defined clades. Genetically related species often share similar metabolic properties, consequently, a system of classification based on phylogeny can be used to predict which species may have useful properties. For example, the biotechnologically important methanol assimilating species are found in two major genera, Komagataella and Ogataea. Many of the yeasts known to produce sophorolipids, which are surfactants, are found in the Starmerella clade. Other examples are known for species that produce high levels of ethanol or that synthesize polyols.